1. Field of the Invention
The present invention relates broadly to the utilization of the crankcase vapors in gasoline powered internal combustion engines and, more particularly, is concerned with the improvement of an automotive fuel saving system which utilizes such vapors.
2. Description of the Prior Art
The directing of crankcase vapors into the air intake system of an internal combustion engine is an old, well known art. U.S. Pat. Nos. 1,286,930 issued in 1918 to Buckner and 1,299,790 issued in 1919 to Scott, disclose early systems for utilizing crankcase vapors.
Basically, the crankcase vapors of internal combustion engines consist of two major components, the blowby gases, i.e., the carbureted mixture plus exhaust gases passing by the rings of the piston, and vaporized and entrained particles of the lubricating oils in the crankcase that have been aerified or vaporized due primarily to agitation. The blowby gases contain large amounts of hydrocarbon gases that have a relatively high fuel energy content and can be burned in the engine to provide power that might otherwise be wasted. The aeriated lubricating oil in the crankcase vapor frequently contains relatively large and heavy particulate matter. Generally, without further breaking down of these particles, they are detrimental to passages in the carburetor, and in modern systems they build up and eventually clog the conventional PCV (positive crankcase ventilation) valve.
While many systems for utilizing crankcase vapors have been proposed in the past, none have proven to be as satisfactory as the system disclosed in U.S. Pat. No. 4,279,236 which issued July 21, 1981 to the inventor of the present invention. The system of the aforesaid patent primarily includes three air flow circuits for efficiently handling crankcase vapors in a substantially maintenance free manner. In a first air flow circuit, ram air captured by an air scoop and cooperating with an aspirator draws crankcase vapors from the crankcase of the internal combustion engine. Heavy particulate matter in the crankcase vapor is separated, heated and further vaporized by a heat exchanger cooperating with an exhaust manifold of the engine. A second aspirator in the first circuit draws the vaporized particulate matter back into the original vapor stream of the first air flow circuit. The crankcase vapors mixed with the incoming ram air are then directed into the interior cavity of the carburetor air filter. In a second air flow circuit, ram air captured by another air scoop and filtered in the circuit is directed into the crankcase and carburetor air filter cavity, while in a third air flow circuit, filtered air is drawn through a variable annular orifice and metered in accordance with intake manifold pressure into the engine air intake system below the carburetor throttle plate.
While this system of the aforesaid patent accomplishes its intended purpose in an uncomplicated and efficient manner, there is need for improvement in its operating efficiency. The system relies on the automobile fan to boost the ram air flow, so that air flow will be present even though the car with the engine running is not in motion. Predominately, however, the quantity of air entering the air scoops is a function of the speed of the vehicle. Under some operating conditions, reliance upon fan and car motion for creation of ram air flow is less desirable than more direct reliance, for example, upon the revolution per minute (rpm) level of the car engine. Therefore, a need exists for improving the design and efficiency of the system without eliminating any of the advantages fostered by the system in utilizing the crankcase vapors as supplemental fuel.